Construction of hydropower schemes, especially in tropical and sub-tropical regions, can in cases have adverse health impacts on people in the immediate catchment area and downstream of the construction site.  It is essential that public health risks are adequately assessed and addressed, while at the same time opportunities to improve public health benefits are considered.

Some vector borne diseases can be associated with reservoir development , for example malaria and schistosomiasis, and schemes constructed in malaria prone areas have the potential to increase transmission of this disease.  People subject to resettlement can be more at risk from health problems where stresses are created by the new project development; i.e. a poorly managed project could result in lack of jobs or income, poor sanitation, or contaminated water supplies.  Loss or contamination of traditional food sources and access to traditional fisheries would exacubate project-induced health issues.  Anaerobic decay processes in large reservoirs has in some cases increased levels of contaminants such as mercury in fish through bio-accumulation.